Junction box

Abstract: This invention provides a junction box which can easily bridge and separate terminal portions of conductive plates provided in the box. Bus bars 2 are arranged vertically and in parallel in the box. A cover 1 of the box is provided with an opening 3 which is closed and opened with a lid 5. A shorting terminal 9 is mounted by guides 18 on a rear side of the lid 5 slidably in a direction of bridging the bus bars 2. The shorting terminal 9 has contact portions 11 which are spaced from each other by the same distance as that existing between the bus bars 2 and adapted to elastically clamp the bus bars 2. The shorting terminal is accommodated in a casing 13. When the lid 5 is closed, each bus bar 2 enters into the corresponding contact portion 11 of the shorting terminal 9 to close the shorting circuit. When the lid 5 is opened, the bus bar 2 leaves from the contact portion 11 to open the shorting circuit.

Description: This invention relates to a junction box to be used for internal wiring in a motive vehicle and the like and more particularly to an improvement of a shorting construction of conductive plates in the box. It is often necessary in such a junction box to draw and insert a shorting terminal from and into terminal portions of conductive plates which constitute a shorting circuit upon, for example, inspecting it. Heretofore, at such a time, the shorting terminal is drawn out from the terminal portions after a lid mounted on a top wall of a box body is opened and the shorting terminal is inserted into the portions again after inspection. Then, the lid is closed. This prior arrangement for a junction box is known from US Patent No. 3 917 371. That is, heretofore, the inspecting process of the shorting circuit was troublesome because the shorting terminal had to be drawn and inserted manually in addition to opening and closing the lid. As a result it may be dropped by accident into a confined space due to its small size. We are also aware of European Patent Application No. EP-A-0 476 654 which discloses a wiring structure according to the preamble of claim 1 in which a shorting terminal is provided fixedly on the lid portion. An object of the present invention is to provide a junction box which can easily bridge and separate terminal portions of conductive plates provided in a box body. In order to achieve the above object, we provide a junction box which comprises: a box body having an opening; a lid pivotably mounted on said box body to close and open said opening; metal conductive plates provided in said box body for constituting an electrical circuit, each plate being provided with a terminal portion; and a shorting terminal for bridging said terminal portions when said lid closes said opening, characterised in that said terminal portions of said conductive plates are arranged along said opening, and said lid is provided with springs which push said shorting terminal to said conductive plates. In the junction box of the present invention, when the lid is opened, the shorting terminal mounted on the rear side of the lid exits from the terminal portions of the conductive plates to separate the contact portions. When the lid is closed, the shorting terminal contacts with the terminal portions of the conductive plates to bridge the terminal portions. When the lid is closed, the shorting terminal is pushed onto the terminal portions of the conductive plates by an elastic force of the spring to maintain a contacting condition. According to the present invention, it is possible to carry out an engagement and disengagement of the shorting terminal with the terminal portions of the conductive plates simultaneously with being closed and opened, thereby enabling ready inspection. It is also possible to avoid accidental dropping of the shorting terminal since it is mounted on the lid. Since the terminal portions of the conductive plates are arranged in parallel with the opening in the cover, the shorting terminal is positively pushed onto the terminal portion by the spring, even if any errors occur in an arranging position in a direction perpendicular to the opening. There is now described, by way of example, one embodiment of the present invention with reference to the figures in which: Figure 1 is a perspective view of a second embodiment of the junction box of the present invention; Figure 2 is an exploded perspective view of parts on a side of a shorting terminal; and Figure 3 is a cross-sectional view of the shorting terminal shown in Figure 2, illustrating a position in which the terminal is connected to bus bars. An embodiment of a junction box in accordance with the present invention is illustrated in Figures 1 through 3. A box like cover 1 opening downwardly is mounted on a top wall of a box body in which conductive plates constituting an electrical circuit are provided. In this embodiment, a pair of bus bars 20 which act as terminal portions constituting a shorting circuit in the box body are arranged horizontally along the top wall of the cover 1 and spaced from each other at a certain distance horizontally. The cover 1 is provided on the top wall with an opening 3 above the bus bars 20. A lid 5 is pivotably attached to one side edge of the opening 3 to close and open it. A shorting terminal 21, as shown in Figure 2 is made of an elongated conductive plate a center portion of which is bent backwardly from opposite end portions. The center portion serves as an attaching portion 21a while the opposite end portions serve as a pair of contact portions 21b. A casing 22 for accommodating the shorting terminal 21 is made of a synthetic resin material and provided on opposite ends of a front side with windows 23 which receive the contact portions 21b. Two attaching pins 24 (see Figure 3) provided on the center portion of the casing 22 pass through apertures 25 formed in the attaching portion 21a, thereby retaining the shorting terminal 21 to the casing 22. Thus, the shorting terminal 21 is movably attached to the casing 22 so that the terminal 21 can be moved within a certain distance in a direction perpendicular to the portion 21a in the casing 22 by means of a guiding action of the attaching pins 24. Compression coil springs 26 are disposed between the contact portions 21b of the shorting terminal 21 and the lid 5. The casing 22 for the shorting terminal 21 is attached to the rear side of the lid 5 in opposition to the bus bars 20 by inserting stepped portions 22a formed on opposite lower sides of the casing 22 between pawls 27 projecting outwardly from the rear side of the lid 5 while the compression coil springs 26 are being compressed. Then, the contact portions 21b of the shorting terminal 21 project from the windows 23 in the casing 22 by means of an elastic force of the coil spring 26. In this embodiment, when the lid 5 is closed, the contact portions 21b of the shorting terminal 21 are pressed onto the bus bars 20 against the compression coil spring 26, thereby closing the shorting circuit, as shown in Figure 6. When the lid 5 is opened, the shorting terminal 21 is spaced away from the bus bars 20, thereby opening the shorting circuit. According to this embodiment, it is possible to carry out the processes of attaching and detaching the shorting terminal 21 to and from the bus bars 20 in connection with operations of opening and closing the lid 5. In addition, since the shorting terminal 21 is biased by the compression coil springs 26 to project forwardly from the casing 22, even if there is any error in a vertical position of the bus bars 20, the error is cancelled by the spring action so that the shorting terminal 21 can positively contact with the bus bars 20.

Claims: A junction box comprising: a box body having an opening (3); a lid (5) pivotably mounted on said box body to close and open said opening (3); metal conductive plates (20) provided in said box body for constituting an electrical circuit, each plate (20) being provided with a terminal portion; and a shorting terminal (21) for bridging said terminal portions when said lid (5) closes said opening (3), characterised in that said terminal portions of said conductive plates (20) are arranged along said opening (3), and said lid (5) is provided with springs (26) which push said shorting terminal (21) to said conductive plates (20).

Inventors: WAKATA SHIGEKAZU, WAKATA, SHIGEKAZU, WAKATA, SHIGEKAZU C/O SUMITOMO WIRING SYS LTD
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1994
Main classification: B60R16
IPC codes: H01R31, H01R13, H02G3, H01H9